Device for the automatic control of camber flaps and the like for airplanes



Nov. 16, 1937.

DEVICE FOR THE AUTOMATIC R. LEVY 2,099,368

CONTROL OF CAMBER FLAPS AND THE LIKE FOR AIRPLANES Filed Feb. 13, 1936 40 Serial No. 15,908, for

Patented Nov. 16, 1937.

UNITED STATES PATENT OFFICE I 2,099,368 DEVICE FOR THE AUTOMATIC CONTROL OF CAMBER FLAPS AND THE LIKE PLANES FOR Am Ren Lucien Levy, Montrouge, France, assignor to Socit dlnventions Aeronautiques et Mecaniques S. I. A. M., Fribourg, (Suisse) Application In France 1 Claim.

2. The hinge moment 'resulting from the reaction of air on the flap is rigorously limited to a 1.5 definite value, so that any increase of this stress (which might result either from an increase of speed of the airplane, or from a gust of wind) immediatelycauses retraction of the flap, the

duration of this retraction being moreover auto- 20 maticaliy limited to that of the cause which determined it.

The pilot can thus set the flaps-in action whatever may be the speed of the airplane. The flaps will leave the neutral position only when the I speed of the airplane will be lower than or equal to a definite value, and, moreover, their position will, at every instant, be the resultant of the stress of the reaction of air with the permanent stress to which they are subjected owing to the 30 device;

Likewise, when the pilot desires the airplane to fly off, the flaps are, when the airplane is stationary, set to the maximum of their displacement; inproportio-n as the airplane takes up 35 speed by rolling, the flaps are gradually retracted for assuming the position most favourable for flying off. t

Bythe device described in the United States patent application filed on April 11, 1935, under System for controlling the evolutions of a movable object in a fluid, in the name of the applicant, results of the same nature can be obtained by sending in the cylinder, designated by reference number 23 in Fig. 4 of this 45 patent application, air under a definite pressure by means of a distributor allowing at will, either to admit air under this pressure or to allow it to escape for retracting the flaps.

However, this arrangement has an incon- 5o venience in that it requires the presence of a source of compressed air on board, and, consequently, in that it does not allow utilization of the flaps when there is a failure in the supply of compressed air. I

The device according to the present invention is free of these inconveniences, as it is characterized by the fact that the energy necessary for causing downward movement of a flap has been February 13, 1936, Serial No. 63,805

April 5, 1935 stored during the preceding retractionof this flap, so that the setting in action of the latter for downward movement is independent of any source of energy external to the device.

The invention is diagrammatically illustrated in the accompanying drawing: I

.The flap l (operative position)l (retracted position) -pivoted at 2 at a suitable point of the wing A, is controlled by the rod 3 of a piston 4 movable in a hydraulic cylinder 5, which communicates, through a conduit 6, with a hydropneumatic accumulator I, known per se. It is to be noted that this accumulator encloses a piston 8 surmounted by a cushion of compressed air 9, whilst the lowerchamber ll! of the accumulator, underneath the piston, is filled with liquid, the latter also filling up the cylinder 5.

Through a conduit-4|, this cylinder is connected, at the rear of piston 4, with a pump I2 sucking the liquid from a tank l3 through a conduit M. A valve l5, interposed in a pipe I6,

allows, when it is opened, of putting the conduit l l directly in communication with the tank l3.

In its set or operative position, the flap l -is held by the pressure existing in the accumulator 1, the valve l5 being open. The pressure in the accumulator I is determined in such a manner that the flap I automatically retracts when the speed. of the airplane reaches a definite value.

For retracting the flap, the pilot closes the valve [5 and sets the pump l2 in action. The liquid delivered by the latter into conduit ll pushes back piston 4:- the flap retracts and, at the same time, the pressure increases in accumulator I. The energy thus supplied to the accumulator during the retracting operation of the flap will be used during the next downward movement of the flap since at this moment, owing to the fact that the valve I5 is opened, it is the accumulator which will supply the energy necessary for this downward movement.

What I claim as my invention and desire to secure by Letters Patent is:

A device for the control of an airplane camber fiap, or the like, comprising: a hydraulic cylinder, a piston movable in said cylinder, a hydro-pneumatic accumulator, a pipe line connecting this cylinder with said tank on one side of said piston, a liquid tank connected to said cylinder on the other side of the piston, a valve interposed in the pipe "line connecting the cylinder to the tank, a source ofhydraulicpressure allowing to move said piston in the direction corresponding to the increase of the pressure in said accumulator, and means for connecting said piston to the camber flap for actuating the latter in one direction and in the other.

RENE LUCIEN LEVY. 

